Technical Field
The present invention relates to a rotating electric machine having a rotor, such as a motor or generator, and in particular, relates to a permanent magnet embedded-type rotating electric machine wherein permanent magnets are embedded in the rotor.
Background Art
In this kind of permanent magnet embedded-type rotating electric machine, the permanent magnets are inserted into magnet embedding holes formed in the rotor. The permanent magnets are a member that cracks comparatively easily. However, when the permanent magnets crack and divide, the performance of the permanent magnet embedded-type rotating electric machine depreciates. Also, depending on the way in which the permanent magnets crack, the magnets move inside the magnet embedding holes. Further, when movement of the magnets starts, the magnets collide with the inner wall of the magnet embedding holes, and occasions for the magnets to crack increase further. Also, when the magnets move inside the magnet embedding holes, there is a danger of the rotor balance breaking down, and rotor vibration increasing due to the effect of centrifugal force acting on the rotor.